Name: Boiled Onions
Ingredients: white onions; salt; melted butter; pepper

Why it works: Onion and pepper are a kitchen classic. They rank in the top 11% of all ingredient pairs, and cooks put them together in 68,474 recipes. Both carry 2-isopropyl-3-methoxypyrazine, which smells earthy, pea. The science ↓

Boiled Onions

Ingredients

white onions
salt
melted butter
pepper

Directions

Select white onions, cut a slice from the ends, and peel them under water.
Boil the onions in a granite or porcelain-lined saucepan with plenty of boiling water for 20 minutes.
Pour off the water, add more salted water, and cook for 1 hour or until tender.
Drain the onions and serve with melted butter, pepper, and salt.
If the onions are strong, change the water three times while boiling.

Recipe from a historical cookbook (Internet Archive).

Transcribed from a scanned cookbook and modernised for today's kitchens. Where the book gave no heat or time, or said "a moderate oven", the temperatures and times here may be modern equivalents rather than the book's own figures.

Explore the science

The flavor team

The pairs that carry this dish. Each one is judged two ways: how much their aromas overlap, and how often cooks already put them together.

Onion + peppertop 11% of all pairs

Smell alikemoderate

Cooked together68,474 recipes

Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
Onion + buttertop 15% of all pairs

Smell alikemoderate

Cooked together42,912 recipes

Shared aroma: decanal (soap, orange peel).
Butter + peppertop 21% of all pairs

Smell alikemoderate

Cooked together85,593 recipes

Shared aroma: trans-2-nonenal (cardboard, fatty).